258 THE CRINOIDEA CAMERATA OF NORTH AMERICA. 
the two series of the same ray are so nearly in contact as to leave but a nar- 
row space for the insertion of interdistichals. First distichals somewhat 
longer than the succeeding ones, which are quite short; the fourth is axil- 
lary, giving off to the outer sides a row of palmars, which are free from the 
third or fourth plate; to the inner side two palmars, of which the upper 
is axillary, and supports two arms, making three arms to each side of the 
ray. Arms subcylindrical, stout, very little tapering; composed at their 
bases of a few quadrangular pieces, followed by cuneate ones, which deeply 
interlock. Pinnules strong, given off nearly at right angles, and composed 
of short joints; the first very much stouter than the others, given off from 
the second distichals, and wholly or partly incorporated into the calyx. 
Interradial spaces wide, the upper portions rather deeply depressed. The 
plates of the two lower ranges very large, the first being the largest plate in 
the calyx. There are probably five or six rows above, but the number 
of plates in each row is extremely variable; the third contains variously 
from three to five plates at the regular sides, and from four to six at the 
anal side; the fourth row has as many as eight in some specimens. The 
first plate of the anal side is somewhat larger than those of the regular 
sides; it is octagonal, its upper angle being slightly truncated for the recep- 
tion of a narrow anal plate, which is placed between two interbrachials. 
Interdistichals from one to three, longitudinally arranged. Ventral disk 
rather flat, composed of very small irregular pieces; the ambulacra subteg- 
minal, except near the arm bases, but the course of the ambulacra is marked 
by high ridges which diverge to the arms, and form deep depressions all 
along the interambulacral spaces. Orals apparently unrepresented, the sum- 
mit being covered by similar small plates to the rest of the disk. Anal 
opening subcentral, at the top of a well defined protuberance. Column 
round; axial canal large, pentalobate, the outer ends of the lobes widest 
and truncated. 
Horizon and Locality. — Trenton limestone ; Ottawa, Canada. 
Types in the collection of Mr. Walter R. Billings, Ottawa. 
RHAPHANOCRINUS W. and Sp. 
1885. W. and Sp. ; Revision, Part IIL., p. 98 (Proceed. Acad. Nat. Sci. Phila., p. 320). 
1887. Orntert; Ann. des Sci. Géol., Tome XIX., Plate I., Figs. 10, 11. 
1889. S. A. Minter; North Amer. Geol. and Paleont., p. 277. 
Syn. Glyptocrinus (in part) — Waxcorr ; 1883, New Spec. Foss. of the Trenton group of New York, 
p. 2 (Abstr. from the 35th Rep. New York State Museum Nat. Hist.). 
Syn. Glyptocrinus (in part) —S. A. Mitten; Journ. Cincin. Soc. Nat. Hist., Vol. V., p. 37, and 
ibid., 1883, Vol. VI., p. 224. 
